A patterned photoresist layer is formed by a lithography process and is used to pattern various material layers during integrated circuit (IC) fabrication. However, the photoresist scum may be generated during the lithography process. The scum may change critical dimension (CD) and cause the deviation of the patterned IC features, which may further introduce performance and reliability issues and even device failures.
Semiconductor technologies are continually progressing to smaller feature sizes, down to 65 nanometers, 45 nanometers, and below. The scum associated issues are more serious when the CD is smaller. Maintaining a desired CD is even more challenge. Therefore, what is needed is a lithography process to address the above issues.